Series Induction Research Articles

Mathematical Readiness of Freshmen Engineering Students (K-12 2020 Graduates) in Eastern Visayas in the Philippines

Abstract: This study assessed the mathematical and analytical readiness of the incoming first-year college engineering students (K-12 2020 graduates) in Eastern Visayas in the Philippines. First-year engineering students (n=177) participated in the College Math Readiness Test (CMRT), a questionnaire on mathematics subjects that covered Precalculus, Analytical Geometry, Series and Mathematical Induction, Trigonometry, and Basic Calculus: Limits and Continuity, Derivatives, and Integration. The findings indicate that 43% of the respondents were mathematically-college-ready (MCR) and 57% were not-mathematically-college-ready (NMCR). Regarding the NMCR, 39% fared fairly and 18% fared poorly in the CMRT. This suggests that remedial support for mathematics for this group may be required for them to be college-ready for an engineering course. The respondents had the lowest correct mean score for the Integration subjects: Evaluating Differential Equations (15%), Evaluating Definite Integrals (16%), and Solving Area Between Curves (19%). The results of the ranking of the Senior High Schools (SHS) showed that 13 SHS with at least 2 takers and 24 SHS with single takers need to improve their quality of teaching to enhance the mathematical competence of their graduates. The findings of this study were used to identify remediation areas and recommendations to improve the students' college mathematical and analytical readiness. 
 
 Keywords: K-12, college-math-readiness, engineering students, Philippines

Stretchable memory loops and photovoltaic characteristics of organic-inorganic solid-state iron (III) chloride tetraphenyl porphyrin /p-Si(111) nanostructure devices

Iron (III) chloride tetraphenyl porphyrin (FeTPPCl) nanostructure decorated films were grown by thermal evaporation Technique (Edward-306) on p-type Silicon (111)/Al. The picked-up micrographs from the scan electron microscopy (SEM) declared that; the annealed FeTPPCl thin films at 350 ᵒC have a nanostructured decorated surface. An impedance spectrum of the Ag/FeTPPCl/p-Si/Al device is analyzed according to the Series Layer Model (SLM) as LRse[R1C1][R2C2] electrical equivalent circuit. The (Re(Z)-(-Im(Z))) complex-plane of Ag/FeTPPCl/p-Si/Al device is characterized by two composed semicircles with series resistance and induction behavior at higher frequencies. These results may be useful in Organic/Inorganic non-volatile memory scalable devices dependant on the electro‐resistive behavior. There are anomalies recorded types of cyclic (I–V) characteristic curves for the manufactured devices at different backward biasing voltages (under dark condition and illumination at room temperature). The power conversion efficiency (PCE) is 5.73 % at the power of the incident light intensity (Pin = 80 mW/cm2), whereas the projected area of the top electrode ∼ 73.6 × 10−3 cm2. The ideality parameter was larger than unity and the estimated barrier height is 0.46 eV. The series Rs and shunt Rsh resistances are characterized under different backward biasing voltage Vrev = {-2, -3, -4, -6−8, and -10 V} and a constant forward biasing voltage 5 V. When the backward voltage was stretched toward lower voltages (-4, -6, -8 and -10 V), Rsh is decreased as following: Rsh = 4.62, 4.73, 4.78, and 4.87 kΩ, respectively. The maximum values of the change in current (ΔIm) and resistance (ΔRm) are estimated and modulated, mathematically, corresponding to its backward biasing voltages. These results may be supporting utilizing this device in current and resistance electrical switching dependent backward biasing voltage application.

Analysis of Azimuthal Partition Periodic Disk-Loaded Coaxial Structure for Bifrequency MILO Using Equivalent Circuit Approach

In this article, an equivalent circuit approach has been used to study the bifrequency generation by the azimuthally partitioned axially periodic metal disk-loaded coaxial structure. Considering the effect of all harmonics present within the structure and using an equivalent circuit approach, the expression of the equivalent series inductance per unit length and equivalent shunt capacitance per unit length has been obtained for this equivalent transmission line. In addition, with the help of computed equivalent series induction and equivalent shunt capacitance, expressions for the dispersion relation, phase velocity, and characteristic impedance have been obtained. The maximum possible frequency difference (i.e., bandwidth) between the modes (i.e., resonating frequency) and its region of operation have also been analytically computed. Finally, the parametric studies have been performed to find out the effect of structural parameter variation on dispersion behavior. In order to validate the numerical analysis, the structure has been first simulated with the help of CST microwave studio, and then, the analytically obtained results (such as dispersion behavior and phase velocity) have been compared with the results obtained from simulation. The comparison of results shows that the relative error is below than 5%, which shows a good agreement between them.

Production of Various Types of Poultry in Bulgaria for the Period 2010-2018

Poultry farming has always been a major part of animal husbandry in every country. Bulgaria is no exception and has a long-standing tradition in the breeding and production of various types of poultry. In reality, our country was mainly producing chickens, laying hens and eggs in the beginning, but was also successful in the breeding of ducks, turkeys, geese, yurts and other feathered more extravagant species, such as quails, ostriches, pheasants, etc. The main purpose of this article is to analyze the production of different types of poultry in Bulgaria for a sufficiently long period of 9 years, to be able to predict trends and changes that may occur in different types of poultry in the country and to determine not only which ones shall have a leading role for specific regions in Bulgaria, but also the ways to increase their effective production in the direction of closing the production and sales cycle with poultry products processing and reaching the end customer. The article uses methods of situation analysis, time series analysis, induction, deduction, extrapolation, trend derivation and logical dependencies, method of adding value and creating a final product.

Pattern Extraction of Topsoil and Subsoil Heterogeneity and Soil‐Crop Interaction Using Unsupervised Bayesian Machine Learning: An Application to Satellite‐Derived NDVI Time Series and Electromagnetic Induction Measurements

AbstractThe link between remotely sensed surface vegetation performances with the heterogeneity of subsurface physical properties is investigated by means of a Bayesian unsupervised learning approach. This question has considerable relevance and practical implications for precision agriculture as visible spatial differences in crop development and yield are often directly related to horizontal and vertical variations in soil texture caused by, for example, complex deposition/erosion processes. In addition, active and relict geomorphological settings, such as floodplains and buried paleochannels, can cast significant complexity into surface hydrology and crop modeling. This also requires a better approach to detect, quantify, and analyze topsoil and subsoil heterogeneity and soil‐crop interaction. In this work, we introduce a novel unsupervised Bayesian pattern recognition framework to address the extraction of these complex patterns. The proposed approach is first validated using two synthetic data sets and then applied to real‐world data sets of three test fields, which consists of satellite‐derived normalized difference vegetation index (NDVI) time series and proximal soil measurement data acquired by a multireceiver electromagnetic induction geophysical system. We show, for the first time, how the similarity and joint spatial patterns between crop NDVI time series and soil electromagnetic induction information can be extracted in a statistically rigorous means, and the associated heterogeneity and correlation can be analyzed in a quantitative manner. Some preliminary results from this study improve our understanding the link of above surface crop performance with the heterogeneous subsurface. Additional investigations have been planned for further testing the validity and generalization of these findings.

Dynamical and steady state performance analysis of DC series motor and induction motor powered by an autonomous PV generator using MPPT

This paper presents the dynamical and steady state analysis of DC series motor and induction motor fed by photovoltaic generator at different solar irradiance levels. The maximum power point of current/voltage (I/V) characteristic of the PV generator is achieved for different solar intensities, by utilising an open voltage method. The nonlinear operational behaviour of (I/V) characteristics of the PV generator at various solar intensities and the magnetisation curve of the ferromagnetic material of the DC series motor are modelled by high order polynomial mathematical expressions. The dynamical and steady state analysis of the DC series motor and induction motor fed by PV generator at different solar intensity has been tested and investigated; also the dynamical and steady state analysis of DC series motor and induction motor is also farther investigated and studied as a step change in solar intensity levels with fixed loads torque for both motors. All numerical simulations are executed using MATLAB software.

Dynamical and steady state performance analysis of DC series motor and induction motor powered by an autonomous PV generator using MPPT

This paper presents the dynamical and steady state analysis of DC series motor and induction motor fed by photovoltaic generator at different solar irradiance levels. The maximum power point of current/voltage (I/V) characteristic of the PV generator is achieved for different solar intensities, by utilising an open voltage method. The nonlinear operational behaviour of (I/V) characteristics of the PV generator at various solar intensities and the magnetisation curve of the ferromagnetic material of the DC series motor are modelled by high order polynomial mathematical expressions. The dynamical and steady state analysis of the DC series motor and induction motor fed by PV generator at different solar intensity has been tested and investigated; also the dynamical and steady state analysis of DC series motor and induction motor is also farther investigated and studied as a step change in solar intensity levels with fixed loads torque for both motors. All numerical simulations are executed using MATLAB software.

Vibration Analysis of Motor Stator

Motor vibration is one of the main causes of the motor noise, and the vibration of the motor also brings great harm for the safe and reliable operation of the motor load system. The vibration and noise level is one of the essential elements in evaluating the electrical machines quality. Accurate calculation of the stator natural frequencies and harmonic response of an electrical machine is essential to the prediction of the vibration. This paper takes the common Y series induction motors as the sample. The motor is a complex electromechanical coupling system, which includes stator and rotor. The finite element analysis is used to study on the stator modal shapes and natural frequencies of the induction motor. Then this paper calculates the electromagnetic force by using the finite element method, and gets the spectrum distribution of the radial electromagnetic force. Thus it provides a good method for the motor design by predicting natural frequency and optimizing the motor parameters to avoid resonance. All of them provide theory fundamental basis and technical support for reducing vibration and noise of the motor.

The Application of the Niching Genetic Algorithm to Optimum Design of the YKK Series Induction Motor

In order to get the YKK series motors to the ultimate purpose of achieving energy-efficient, and to meet the various request constraints set forth in the in the actual production, the paper introduces the niche genetic algorithm to the optimization of the motor design. For the forming structure of medium-sized high-voltage stator coils and the actual situation of three round relative fixed size, this article makes a corresponding improvements to the niche genetic algorithm, the proposed approach surmounts effectively the local convergence problem of standard genetic algorithm. The experimental results demonstrate that: compared with the initial program, the ultimate design results of the electrical motors meet the technical specifications of the proposed efficiency motor. Furthermore, the size of motor has been reduced, which saves the effective materials of the motor. It prove the feasibility and advantages of niche genetic algorithm’ improvement, and more important is, it verify the practical engineering value.

Analysis of the structure‐dynamic behaviour of an induction machine with balancing kerfs

PurposeTo present results of research closely linked with real life applications. It resumes work of a period of about two years.Design/methodology/approachApplying the finite‐element method (FEM) the impact of balancing kerfs in the bars of squirrel‐cage rotors of a small scale, mass series induction machine (IM) is studied. For the analysis and design optimization of the IM both, 2D electromagnetic, multi‐slice and 3D structure‐dynamic models are considered. Introducing and applying a novel 2D‐3D force‐transformation scheme, all possible balancing variants of the IM are studied in terms of electromagnetic and mechanical behaviour.FindingsThe obtained results lead to a significant improvement of the studied IM. In fact, it is found, that the method of balancing the rotor by carving the rotor bars results in higher unbalanced pull rather than reducing it. This is due to electromagnetic unbalance caused by balancing. Hence, the IM is no longer balanced in series production. This again leads to a major economic benefit.Research limitations/implicationsUsing the FEM for simulation of structure dynamic problems is often limited to how the boundary layers are handled. In real life materials are not “connected” but glued or clamped. Therefore, the behaviour can only be adopted by manipulating the material parameters derived from iterative parameter adoption by measurement.Practical implicationsOwing to the findings the IM is no longer balanced in series production, leading to a significant reduction of costs. In general, the applied methods can be used for the analysis and optimization of any kind of manufacturing or tolerance problem of electrical machines such as various kinds of eccentricity, punching kerfs, broken bars, magnetization errors in permanent‐magnet machines, etc.Originality/valueThis contribution gives a close insight of how to study the impact of manufacturing and tolerance problems of electric machinery, applying the method to an IM with balancing kerfs.

1043 Surgical aspects of induction chemotherapy in stage II-III breast cancer

The issue considered is whether surgery is affected by induction chemotherapy in stage II-III breast cancer. This aspect of breast cancer management has not until now been totally clarified and therefore has taken the attention of our study group, particularly with regard to peri-operative morbidity. Sixty patients with locally advanced/innammatory breast cancer or large T2 N0-1 tumor treated by induction chemotherapy have been evaluated: at the time of diagnosis, 20 cases were in stage IIIB (inflammatory), 23 in stage IIIA/IIIB (non-inflammatory), and 17 cases in stage IIA/IIB. Induction chemotherapy schedule was: CMF (<i>Ctx 150</i><i>mg\d days 1–14; Mtx 40</i><i>mg/m</i>² <i>days 1, 8; 5-Fu 600 mg/m</i>² <i>days 1, 8</i>) as first cycle, Adriamycin (<i>75</i><i>mg/m</i>² <i>day 1</i>) as second, and CMF as last cycle. The local response to therapy-allowed breast conservation in 12 cases (20%) (4 in stage HIII/IIIB and 8 in stage IIA/IIB). Mastectomy was required in 48 patients (80%) (20 in stage IIIB, 19 in stage IIIA/IIIB, and 9 in stage IIA/IIB), in 6 cases associated with immediate breast reconstruction, and in one case with full-thickness chest wall resection and prosthetic reconstruction. Surgery was performed 4 to 6 weeks after the last cycle of chemotherapy. Chemotherapy was then continued for a total of 6 cycles. All patients underwent postoperative radiotherapy on the chest wall or whole breast depending on the surgical procedure. There was no operative mortality. Perioperative morbidity was observed in 11 patients (18%): neutropenia that delayed surgery in 5 cases (8%); wound infection with delayed healing in 2 cases (3%); seroma in 3 cases (5%); partial necrosis of cutaneous flap in one case (1.5%); pneumonia and pleural effusion in one case (1.5%). No upper extremity lymphedema was observed. Complications were easily managed in all cases, determined only a slight increase of hospitalization and generally did not delay postoperative therapy. The 60 patients who underwent induction chemotherapy were compared with 60 patients treated directly by surgery. The two groups were matched according to age, type of surgery and time of operation. No significant difference (<i>P</i>=0.077) was found between the two groups in the incidence of postsurgical complications. As a conclusion, in our series induction chemotherapy did not seem to influence the outeome of surgery in terms of perioperative morbidity.

Optimization of ultrasonic transducers

The so-called KLM-model for ultrasonic transducers is employed to optimize transducer design. Some new performance characteristics are defined which change monotonically with design parameters. These characteristics are based on the area of the envelope of the echo waveform produced by the transducer and of the corresponding amplitude spectrum. The efficiency of the transducer is defined by the round trip energy factor. The performance characteristics are used in a composite performance measure, which is then employed as a criterion in the optimization procedure. Two transducers are investigated: for medical imaging purposes and for spectral analysis of clinical echograms. The influence of electrical matching, backing impedance, matching layer impedance, bond line thickness and series induction on the optimized transducers is investigated.

Microporosity in casting alloys.

Three series of tensile test pieces were produced using a nickel base partial denture casting alloy. For the first series induction heating was employed, for the second a resistance crucible, and for the third an oxy-acetylene torch. Samples from each series were sectioned longitudinally, mounted, polished and examined microscopically for evidence of microporosity.

The effects of remelting on the mechanical properties of a nickel base partial denture casting alloy.

Three series of tensile test pieces were produced using a nickel base partial denture casting alloy. For the first series induction heating was employed, for the second a resistance crucible, and for the third, an oxy-acetylene torch. In each series the same metal was cast sequentially a number of times and all test pieces so produced were subjected to mechanical testing. The mechanical properties were found to vary according to both the number of times the alloy was cast and the method of heating used to render the alloy molten.

Elective induction of labor at term

A study of 1,000 consecutive deliveries has been presented with an analysis of the results in 301 unselected cases in which labor was induced as compared with 699 not induced. In this series induction has been shown to be a safe procedure, with a slight tendency toward shortened labor.

Moteurs a Collecteur a Courants alternatifs

THE title leads one to believe that the author is going to deal with at least all the principal types of modern alternate-current commutator motors, whereas the book is practically restricted to a consideration of the series induction and conduction motors. Shunt induction motors of the commutator type are occasionally touched upon, but all remarks concerning these must be considered as quite erroneous. Generally speaking, the number of mistakes is too great. Moteurs a Collecteur a Courants alternatifs. By Dr. F. Niethammer. Pp. 131. (Paris: L'Éclairage Électrique, 1906.)